The goal of this Phase II program is to design and develop an innovative, new actuator, combining FMT's concepts of the "magscrew" and "magspring" to produce a highly efficient, long-lived, compact actuating system optimized for ventricle assist devices (VADs). The magscrew, which has already been successfully demonstrated in a total artificial heart actuator, offers many advantages as a driver for implanted blood pumps; namely compactness, reduced wear and fatigue, and nearly lossless conversion of rotational motion to translational actuation. The addition of the magspring is specific to VAD applications. With only one pumping chamber, the return stroke of the actuator is used to store energy in a magspring and, thus, reduce the physical size and motor power losses of the actuator. The magspring concept was successfully validated in Phase I, and results in a rugged, efficient VAD. The Phase II specific aims are to: 1) construct a final, optimized VAD design integrating the magscrew/magspring actuator and a CCF biolized blood pump, 2) develop a prototype controller for the VAD system, 3) perform in vitro endurance tests of the VAD system; and 4) perform in vivo tests of the VAD system in calves. PROPOSED COMMERCIAL APPLICATIONS: As a consequence of this research effort, a very long-lived, reliable VAD - one with a 108-mm diameter, a 58-mm thickness, and a 950-g weight - will be available to the permanent implant market. This market has been estimated to include 30,000 candidates per year, according to a 1991 report published by the Institute of Medicine. A sufficiently safe, effective VAD could have a market as large as 200,000 cases per year.